Method extend

crates/kernel_cmdline/src/utf8.rs:260–264

Note this is O(N*M), but in practice this doesn't matter because kernel cmdlines are typically quite small (limited to at most 4k depending on arch). Using a hash-based structure to reduce this to O(N)+C would likely raise the C portion so much as to erase any benefit from removing the combinatorial complexity. Plus CPUs are good at caching/pipelining through contiguous memory.

(&mut self, iter: T)

    // combinatorial complexity.  Plus CPUs are good at
    // caching/pipelining through contiguous memory.
    fn extend<T: IntoIterator<Item = Parameter<'other>>>(&mut self, iter: T) {
        for param in iter {
            self.add(&param);
        }
    }
}

/// A single kernel command line parameter key